A valve timing controller has a driving rotor rotating with a crankshaft and a driven rotor rotating with a camshaft, and controls a rotation phase of the driven rotor relative to the driving rotor using planet movement of a planet gear.
JP 4360426 B2 describes a valve timing controller in which a driving side external gear part and a driven side external gear part of a planet gear respectively mesh with a driving side internal gear part of a driving rotor and a driven side internal gear part of a driven rotor in the eccentric state. When the valve timing controller is applied to an internal combustion engine, a large drive ratio can be obtained while the valve timing controller is downsized. In JP 4360426 B2, the planet gear is supported by a planet carrier through a planet bearing, such that smooth planet movement is achieved. An elastic component is interposed between the planet carrier and the planet bearing, and produces a restoring force. The planet gear is biased by the restoring force through the bearing to the eccentric side relative to the driving rotor and the driven rotor. There is no backlash in an engagement portion at which the driving side internal gear part and the driving side external gear part mesh with each other, and there is no backlash in an engagement portion at which the driven side internal gear part and the driven side external gear part mesh with each other, such that abnormal noise and wear are restricted from being generated.
In JP 4360426 B2, the planet bearing has double rows of spherical rolling elements disposed between an outer wheel that supports the planet gear from a radially inner side and an inner wheel supported by the planet carrier from a radially inner side.